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If you sell physical products, you either have to carry your own inventory, or sign-up with a program that allows drop-shipping. Affiliate sales (see below) are preferred by most online marketers, because the hassle of inventory and shipping is totally off your back, and the burden of someone else. On the other hand, digital products are very unique. A digital product might be an ebook, a video, an online course, or a membership site. With Amazon, you can either be an affiliate or a seller. As an affiliate, the storefront is taken care of for you. As a seller, you have to add your products to the system, and make sure they have good titles product descriptions, and photos that will help it to sell.